Process of chemical printing



June 10, 1930. H. E. BROOKBY PROCESS OF cnmxczmrnmwme Filed Aug 29, 1927 Patented June 10, 1930 UNITED STATES.

PATENT OFFICE HARRY E. BBOOKBY, OF EVANSTON, ILLINOIS, ASSIGNOR' TO THE UNITED STATES GYPSUM 00., OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS rnocnss or CHEMICAL PRINTING Application filed August 29,- 1927. Serial No. 216,004.

This invention relates to the manufacture of wallboard and plasterboard but more particularly to a method and a device for imprinting trade names, trade marks, etc. there Due to the rough, fibrous texture of the covering material used on these boards and the continuous method of manufacture, 1t is impractical to print trade marks, etc., thereon a process and a device whereby such trade marks etc., can be printed on the boards during their process of manufacture andat the same time, secure the fine clean cut lines and letters which give the boards a neat appearance. a

This is secured by means of what term chemical printing. Chemical printing 1s simply the formation of a colored insoluble compound on the surface of the board by the chemicals ina printing solution with the chemicals of a developing solution. Various and sundry features will govern the quality of the printing obtained, such as the perfection of the printing wheels and the care with which the equipment is installed and adjusted and the quality and proper concentration of the chemicals used. The process is substantially as follows:

The printing is impressed on the board by a printing wheel to which is fed a chemical solution which I term a printing chemical. The board moves forward sufficiently to allow the water of the chemical solution to become dry and thus, impregnate the fibrous cover of the board with'the printing chemical in the desired print pattern. Over this is impressed, by means of a developing wheel, a

- chemical solution'which penetrates? the fibrous board cover and reacts with the chemical used in the printing to develop an insoluble compound within the fabric of the covering material itself and thus the printed pattern becomesvisible. Various formulae are necessary in producing different colors. The following tabulation sets this forth very clearly Printing solution i gg Results Color Lead acetate and Ammonium sul- Lead sulphide Brown.

acetic acid. p e. and atmmonium ac a e. Lead acetate and Potassium chr0- Lead chromate Yellow.

acetic acid. mate. pogaassium acea e. Ferric nitrate. Sodium ierrocya- Ferric ferrocya- Blue.

mde. nide and sodium nitrate. Copper sulphate. Sodium ferrocya- Copper terrocya- Red.

mde. nide and sodium sulphate.

In the above printing and developing solutions the salts used for each are dissolved in water. The printing solution is disposed on the board by the letters of the printing wheels. The solution penetrates the fibrous cover of the board and the water evaporates within a few feet of travel of the board onto the belt of the machine. The developing solution is then disposed on the board by the developing roll and the color of the print is immediately developed. p

' In the accompanying drawings which show part of the'machine and device to carry out this invention Fig. 1 is a cross sectional elevation of a %eveloping device taken along the line 11 of Fig. 2 is a plan view of the same device taken along the line of 2-2 of Fig. 1.

The developing solution is supplied from a tank (1) through a pipe and trough (2) to feed tank (3). A feed roll (4) runs'continuously dipped into this solution which it transmits to a fluted metal feed roll' (5) which in turn transmits the developer to the developing roll (6) which has a rubber rim (7) The developing roll (7) and the feeder rolls are carried in the same framework (8) which is fastened to another framework (9) lower; the lower member has the function of preventing the frame (8) to drop if the flow of the board is interrupted, set screws leing provided to adjust the amount of drop permitted. The upper member carries 2 hooks. One supports the spring 16) which'in turn supports a sling (15) which maintain the frame (8) in position during the operation of the machine and yet allowing a certain amount of resiliency.

The other hook is shorter and engages the sling (15) when the framework 8) is raised up out of the way when the device is in oporation.

The printing device is essentially the same save in that the roller corresponding to roller (4) as shown should be of metal. The roller corresponding to roller (5) should be rubber and the printing wheel should be all metal. It is well to note at this point, that the metal rollers and wheels or parts thereof, or any other metal parts which come in contact with the developing or printing chemicals, should be of Monel metal or other alloy of such material that they will not be attacked by the developing chemicals.

In operation, in the continuous gypsum board process, it has been found that the printing wheel should be approximately 125 feet from the sizing rollers of the machine. The developer wheel should be about feet from the print wheel and the v developer should be at least 100 feet from the cut-off knife. As the board travels over the printing wheels and developing wheels it should pull them rather than push them. These should be arranged so as to make approximately one fourth of a revolution from the application of the printing and developing solution to the wheel until the wheel transmits the solution to the board passing thereunder.

While the device and method set forth herein have 'proven satisfactory, it is to be understood that minor variations may be made therefrom without departing from the scope of this invention.

Having described my invention, what I claim is:

1. The process of chemically printing trade marks, etc.. on plasterboards during their process of manufacture comprising the applying thereto a printing chemical during the continuous movement of said plasterboards, allowing the same to penetrate the fibrous cover sheet, and thereafter applying a developing chemical, such that the reaction by the two chemicals will produce an insoluble color substance within the surfacing cover sheets of the plasterboard.

2. The process of printing various marks upon plasterboard and wallboard in the process of manufacture comprising the applying first a printing chemical in solution to penetrate the cover sheet, thereafter applying a developing chemical in solution and allowing the chemicals to react and dry, the reaction depositing a colored insoluble compound within the fibrous covering of the plasterboard or wallboard, the said process being accomplished during the continuous movement of said boards.

3. The process of chemically printing distinguishing marks upon plasterboards or wallboards in the process of manufacture comprising applying the distinguishing marks to the boards in the nature of an aqueous solution of a chemical, allowing the solution to penetrate the cover sheet and dry, applying a developing chemical which reacts with the previous print to produce a colored insoluble chemical compound imprinted Within the fibrous material of the wallboard or plaster board the said-process being accomplished during the continuous movement of said boards.

4. The process of chemically printing sheets or boardlike unit materials of aqueous solution absorbing surface capacity, comprising the applying thereto a printing chemical during the continuous movement of this material, allowing the same to penetrate the absorbing surface, and thereafter applying a developing chemical such that the two chemicals will produce an insoluble colored compound within the absorbent surface of the sheet material.

5. The continuous process of applying distinguishing marks to moving sheet or boardlike material of liquid absorbing properties, by chemical means, comprising applying separately two chemical solutions which will interact to precipitate colored insoluble compound Within the surface to which they have been applied.

In witness whereof, I have hereunto subscribed my name.

HARRY E. BROOKBY.v 

